The documentary drama tells the story of the only man who survived the wreckage of the World War II Submarine HMS Perseus, which sank unnoticed in 1941. With the help of a team of historians, famous underwater wrecks researcher, writer and professional diver Richie Kohler tries to understand why a simple submariner got involved in the transportation of a secret cargo as part of the high-end spy games between the Axis and the Alliance.
